Green’s Dictionary of Slang

mash v.

[SE mash, to crush, to pulp, hence sexually to render ‘soft’; note Rom. mash, to allure, to entice]

1. [mid-19C+] (US) to beat someone up; to crush.

2. [late 19C+] (orig. US theatre) to make oneself attractive to a member of the opposite sex, to flirt with, to succeed in seduction; thus mashing

3. [1940s+] (US black) to give one what is due; thus mash it on me, give it to me; mash me a fin, loan me $5.

4. [1950s] (W.I.) to seduce, to rape.

5. [1970s] (US) to masturbate.

6. [1980s] (US black) to pass over stolen or contraband goods.

7. [1980s+] (US campus) to kiss, to neck.

8. [1980s+] (US black) to work hard, to commit oneself to a task.

9. [1990s+] to fondle the breasts in an aggressive manner.

10. [2000s] (US black) to have sexual intercourse in an aggressive manner.

In derivatives

mashful (adj.)

[1900s] (N.Z.) amorous.

mashing (n.)

1. [late 19C–1930s] the act of flirting, seducing, making advances; also attrib.

2. [late 19C] used adv., affecting the style of a masher n. (2)

In compounds

mashman (n.)

[2000s] (UK black) a thug.

mash-up

see separate entries.

In phrases

mash it (up) (v.) (also mosh it up)

1. [1950s+] (W.I., Rasta/UK black) to achieve a huge success; to do something well.

2. [1990s+] (W.I.) an expression of encouragement.

mash the fat (v.)

[1970s+] (US black) to have sexual intercourse.

mash up (v.) (also mash in) [late 19C+]

1. (orig. US/W.I.) to destroy, to break, to beat up, of a relationship, to break up.

2. (W.I.) to get oneself into trouble.

3. (W.I.) to cause trouble.

mash with (v.)

[1980s+] (US campus) to kiss, to neck.

SE in slang uses

In phrases

mash flat (v.) [mashing the accelerator pedal]

[1940s] (W.I.) to move along, to make room, as in a crowded bus; also to accelerate a car.

mash the gas (v.)

[1960s+] (US) to accelerate.